Structural panel construction



June 18, 1957 INVENTOR.

CHARLES R. GINSBURG ATTORNEY STRUCTURAL PANEL CONSTRUCTION Charles R. Ginsburg, Toledo, Ohio Application May 18, 1956, Serial No. 585,822

1 Claim. (Cl. 189-34) This invention is particularly concerned with structural units which in one embodiment may constitute the spacing and reinforcing elements adapted to serve as the body portion of a structural element. Devices of this nature have a low weight-to-strength ratio and are desirable as a strain resisting member. These structures are adapted for use as floor panels, for aircraft and building industry as well as a variety of other places.

An object is to produce a new and improved structural unit provided with a plurality of cone-like cells having a high degree of strength and stiffness in combination with lightness of weight and which may be formed of metallic or non-metallic material or combinations thereof.

Another object is to produce a simple and efiicient structural unit which has the important and unique features of construction and assembly hereinafter described.

Other objects and advantages will appear more fully hereinafter and for purposes of illustration but not of limitation, an embodiment of the invention is shown on the accompanying drawings in which Figure l is a perspective view, partly broken away, illustrating a composite structural member and showing one of the structural units partly unfolded;

Figure 2 is an enlarged perspective view of a structural unit showing the manner in which it is formed from two ribbons of bendable sheet material, such as aluminum; and

Figure 3 is an enlarged fragmentary elevation of one of the ribbons after being folded or braided.

The illustrated embodiment of the invention, as shown on Figure 1, comprises a pair of spaced panels and 11 between which are interposed a plurality of closely spaced parallely arranged core units 12 which are adhesively secured in place by a suitable adhesive, such for example as a thermo setting synthetic resin. Suitable resins are phenol formaldehyde or polymerized phenol formaldehyde. A modifier may be added for reducing brittleness in the form of alcohol soluble polyamid or neoprene.

Each core unit 12 is formed from a pair of ribbons 14 and 15 preferably of light gauge sheet aluminum. Figure 2 illustrates the manner in which the ribbons are folded to form a unit. It will be observed that the two ribbons are first disposed at right angles to each other with a portion of the ends lapped. Then successively the ribbons are folded over upon each other, allowing a slight spacing between a bend of one ribbon and the adjacent edge of the other ribbon. First one ribbon is folded at right angles upon the other ribbon, then the latter ribbon is folded in the opposite direction at right angles upon the first ribbon. The folds in each instance are loose to enable subsequent twisting action. This folding is carried out until the desired length of core unit is obtained. After the desired length or predetermined length has been obtained by the alternate folding of one ribbon upon the other, then the structure so formed is extended longitudinally and twisted to oppose the tendency of the structure to unfold, so that each of the sides of the unit is parallel to the opposite side, forming a' generally rectangular structure in cross-section.

An alternate method of forming a core unit consists in effecting a twist as the ribbons are interlaced and at the same time providing the desired spacing of the bent portions of one ribbon from the other. This may be achieved by making the folds over a suitable forming tool.

It will be found that the completed structure has a series of cells 16, each cell being generally V-shaped with opposite side walls 17 and 18 and a closed apical wall 19. It should be observed that in each cell 16 the wall 18 at the front (Figure 2) is relatively long and of S shape, and the rear edge is substantially straight up and down. The lower portion of the front edge portion, as indicated at 20, snugly engaging the other ribbon out at the top, as indicated at 21, there is somewhat more material, the ribbon curving gently over and downwardly as shown. As a result conical cells are formed so that relatively great weight can be supported without danger of buckling. Thus a cone-like support is provided as distinguished from a less substantial cylindrical support.

The cells are alternately arranged; that is one opens to one side of the unit and the next adjacent cell opens in the opposite direction. Thus throughout the length of each unit, the cells are alternately arranged and alternately face in opposite directions. This arrangement obtains, regardless of which of the four sides of the unit is viewed.

When several of the units are arranged in side by side relation, such as indicated on Figure 1 and adhesively secured to the panels 10 and 11, an exceedingly sturdy structure is obtained and one which can withstand very great weights without collapsing. The arrangement of the core units and their inherent form provide a barrier against the flow of air from one side to the other. The various cells trap air and thus form a very satisfactory insulation. In the event that it is desired to permit air circulation between the panels 10 and 11, perforations (not shown) can be formed in the walls of the core units for this purpose.

From the above, it will be manifest that panels of any desired size can be readily made since the length of the core units 16 can be varied as desired, this depending upon the length of the ribbons employed to form the individual core units. Thus from a quantity production standpoint it will be manifest that the core units can be made of any suitable length and width and then severed to the length that is desired for a particular panel structure. The necessity of making the core units or the core specific in size for a definite panel is not necessary and consequently quantity production can be carried out more efliciently and economically. The manner in which the core units are assembled is also of importance from an economic standpoint since they can be placed in sandwich form and adhesively united to the opposite panels quickly and efiiciently.

This application constitutes a continuation-in-part of my application, Serial No. 504,241, filed April 27, 1955 and entitled Structural Unit.

Numerous changes in details of construction, arrangement and operation and choice of materials may be effected without departing from the spirit of the invention, especially as defined in the appended claim.

What I claim is:

A structural member comprising a surface panel formed of a pair of relatively thin sheets of material disposed in spaced parallel planes with opposed inner sides, and a core between said sheets, said core comprising a plurality of core units arranged in juxtaposed parallel relation, each unit comprising a pair of ribbons of sheet material, said ribbons being undulant, each with a series of successively oppositely bent portions and being successively oppositely twisted between the bent portions providing a series of alternately facing cone-shaped cells, the ribbons of each pair being disposed with the surfaces thereof generally at right angles and loosely interlacing with one another, each bent portion of one ribbon passing over .an edge between the bent portions of the other ribbon, thereby providing alternate sharp and bent edge portions along each side of each unit, said units having opposite References Cited in the file of this patent UNITED STATES PATENTS Yarrington Jan. 31, 1893 Pajak Sept. 2, 1952 

